Internal combustion engine-air compressor



1959 H. PETERSEN 2,867,375

INTERNAL comauswxou ENGINE-AIR COMPRESSOR Filed July 30. 1954 2 Sheets-Sheet l O M O Q 0 T l 5 I38 40 23a 4/ I39 6 O MM. Q Q

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INVENTOR. 4? HANS PETERSEN ATTORNEY Jan. 6, 1959 PETERSEN 2,867,375

I INTERNAL COMBUSTION ENGINE-AIR COMPRESSOR Filed July 30, 1954 2 Sheets-Sheet 2 IN VEN TOR.

HANS PETERSEN ATTORNEY mamas INTERNAL COMBUSTION ENGINE-Am COMPRESSUR Hans Petersen, Surth (Rhine), Germany Application July 30, 1954, Serial No. 446,8tl2

In Switzerland January 14, 1949 Public Law 619, August 23, 19% Patent expires January 14, 1969 7 Claims. (Cl. 230-56) The invention relates to an internal combustion engineair compressor of the type wherein each of two cylinder groups located side by side with parallel axes is provided with a pair of oppositely reciprocating pistons, and wherein each piston of the one group is so connected with a piston of the other group that the connected pistons move simultaneously but in opposite directions. In such an engine-compressor the one group comprises the cylinder of the internal combustion engine, and at least a portion of the other group comprises a cylinder of the single stage or multi-stage compressor.

In the conventional internal combustion engine-air compressor of the type comprising two parallel cylinders, the compressor part furnishes not only the output of compressed air but also the scavenging and charging air for the engine part, and it furthermore, serves to store the energy for the return movement of the pistons.

Such conventional engine-compressor has the drawback that it requires large dead spaces in the compressor part which impair the volumetric and thermic efficiency. There is also the danger of a collision of the pistons if, for one reason or the other, the resistance in the dead spaces of the compressor is greatly reduced. Furthermore, the output of the compressor and the compression in the engine part will drop when the valves of the com pressor begin'to leak. Y Y

The invention aims to avoid the mentioned and other drawbacks of conventional structures and to provide an internal combustion engine combined with a single stage or multi-stage compressor in a very compact structure which is readily accessible in all its parts.

The invention further aims to provide, in an assembly comprising two cylinder groups of the mentioned kind, pneumatic energy storage spaces or safety buifers in one of the cylinder groups for the return stroke and for the synchronization of the movement of the pairs of symmetrical pistons which reciprocate separately from each other, and wherein the storage spaces or bufiers may form a common stroke space or two separate stroke spaces or partial stroke spaces.

In the assembly according to the invention one of the cylinder groups with its accessorial parts includes the power generator and the scavenger and charging pumps of the engine 'part,'whereas the other cylinder group contains at least one stroke space for the compression of the air output and at least another space for storing the stitutes the energy storing space and the end parts con-' stitute compressor cylinders, or that a first portion of each as ers end part constitutes a first compressor stage cylinder, the remainder of the end parts being storing spaces, and the mid-length part is arranged and equipped as a second compressor stage cylinder. The division of the end parts in a compressor space and an energy storing space may be accomplished by slots or valves in the cylinder wail. Similarly, an end part of the engine cylindermay be divided in a first portion constructed and equipped as a scavenger or charging air pump and in its remainder portion as a safety buffer in order to prevent a piston leading with respect to the other from striking against the shoulder between the mid-length portion and the adjacent end portion of the cylinder.

The present invention, summarized briefly, includes, in side-by-side relation, an internal combustion or powergenerating cylinder and a power-receiving or air compressor cylinder. In each cylinder a pair of oppositely reciprocating pistons is-provided, and each piston of a cylinder is connected by a rockable lever to the corresponding piston of the other cylinder, for synchronized, conjoint operation, the connection being such as to cause the air compressor pistons to move toward one another in a compression stroke simultaneously with movement of the internal combustion engine pistons away from one another in an expansion stroke. The pistons and cylinders are of stepped formation, to produce in each cylinder, between the pistons, a mid-length stroke space of relatively reduced diameter. This communicatesat its ends with end stroke spaces of a larger diameter and the outer large diameter ends of the pistons work in said end stroke spaces. Associated with the cylinders and pistons are scavenger and charging means, and return movement energy storage means. In all forms of the invention as presently practiced, the first named means is incorporated in the end stroke spaces of the internal combustion engine cylinder. The return movement energy storage means is provided by incorporating, in the air compressor cylinder, stroke spaces that are reduced in length responsive to movement of the air compressor pistons in one direction, and are sealed against the exit of air therefrom duringat least a part of said movement to provide buffer stages that will shift the air compressor pistons, and hence the internal combustion pistons connected thereto, in a return direction.

In the annexed drawing, in which like reference characters designate like parts throughout the several views:

Fig. 1 is a longitudinal sectional view through an internal combustion engine-air compressor formed in accordance with the present invention, wherein parts remain in elevation and other parts are somewhat diagrammatically illustrated,

Fig. 2 is a view similar to Fig. 1 showing a modified form, and

Fig. 3 is a view similar to Fig. 1 showing a second modification.

In the form of the invention-shown in Fig. 1, the reference numeral 1 designates an internal combustion or power-generating cylinder in which is mounted a pair of oppositely reciprocating pistons 2, 3. v

Power supplied from the combustion cylinder 1 is transmitted to an air compressor cylinder 4 disposed in side-by-side, coplanar relation with cylinder 1, which may have, but not necessarily has a length and bore diameter equal to those of cylinder 1. -W0rking in cylinder 4 are oppositely reciprocating compressor pistons 5, 6.

Connecting rods 7 are pivotally attached to the pistons 2, 3, 5 and 6 and to the opposite ends, respectively, of levers 8, 9, rocking upon axles or pins 10, 11, journalled in the opposite walls of the cylinder housing. Preferably, the axles 10, 11 are fixedly secured to their associated levers, to drive such auxiliary assemblies as a fuel injection pump, lubricating oil pump, etc., not shown.

Patented Jan. 6, E59

enemas Cylinder It includes, medially between the opposite ends thereof, a mid-length or intermediate stroke space 13, into which opens a fuel injection nozzle 14. Nozzle 14 is located at the mid-length point of the intermediate stroke space 13, and said intermediate stroke space is closed, at opposite sides of the nozzle, by the pistons 2, 3.

Assuming that combustion of the fuel has taken place at the mid-length location of the intermediate stroke space 13, the pistons 2, 3, will be forced away from another in an expansion or power-generating stroke.

This results in the movement of piston 3 to the right in Fig. 1 a distance sufiicient to uncover, at the conclusion of the expansion stroke, a circumferential series of inlet slots 15 formed in the wall of the cylinder 1 and spaced longitudinally of intermediate stroke space 13 from the injection nozzle 14. At the same time, the piston 2 will have uncovered a circumferential series of outlet slots 16 formed in the wall of cylinder 1 adjacent the opposite endof stroke space 13.

This accomplishes the scavenging of gases from the internal combustion engine cylinder.

At its opposite ends, the cylinder 1 is of increased diameter as compared to'its mid-length portion. As a result, the intermediate stroke space 13, at its ends, opens into end stroke spaces 17, 13, substantially greater in diameter than the diameter of the intermediate stroke space. The outer ends of the pistons 2, 3 are disposed within the end stroke spaces, and are of increased diameter as compared to the diameters of the confronting inner ends of the pistons, the stepped diameters of the pistons corresponding to the stepped diameters of the cylinder.

A shoulder 110 is thus defined at each end of the intermediate stroke space 13, where it communicates with the end stroke spaces. Confronting the shoulders 110 are shoulders 120, 130, defined on the pistons 2, 3, respectively, due to the stepping of the diameters of said pistons. Between each shoulder 110 and its confronting piston shoulder, as a result, there is provided an annular space surrounding the reduced part of the piston, which space is reduced in an axial direction on movement of the combustion pistons toward one another in their return or compression stroke, and is enlarged in an axial direction on movement of the combustion pistons away from one another during their power-generating or expansion stroke.

Mounted in the walls of the end stroke spaces 17, 18, between the confronting shoulders of the cylinder and pistons, are inlet check valves 19, 20, respectively, and outlet check valves 21, 22, respectively. Accordingly, when the pistons 2, 3, are moving through their expansion stroke, valves 19, 20 open, causing air to be sucked into the above mentioned annular spaces as said annular spaces are enlarged axially, said air being sucked into the spaces from atmosphere. On the return stroke of pistons 2, 3, valves 19, 20' will close and valves 21, 22 will open, forcing the air previously sucked into the end stroke spaces into a scavenger air receiver 30, which constitutes the housing of the cylinders, and which is sealed at its opposite ends by. housing covers 31, 32. The air used for combustion with the injected fuel within the mid-length stroke space 13 is that air forced out through valves 21, 22, said air subsequently moving into the space 13 through the inlet slots 15 in the manner shown by the arrows in Fig. 1.

Cylinder 4 has an intermediate stroke space 23 similar to the space 13, and formed in the wall of said space 23,

, medially between the opposite ends thereof, is an opening on the expansion stroke of pistons 5, 6, air will be sucked the mid-length stroke space 23, and on return movement of said pistons 5, 6, the air will be forced out of the space 23, through the now open valve 25. Valves 24, 25 are mounted in a conduit 33. The inlet end of the conduit, shown at the right in Fig. l, is in communication with atmosphere, and the other end of the conduit opens into a compressor tank, not shown.

At its opposite ends, the relatively reduced space 23 opens into end stroke spaces 26, 27 of the compressor cylinder. These are substantially greater in diameter than the space 23. As a result, shoulders are defined in the cylinder at the inner ends of the end stroke spaces 26, 27, and confront shoulders 150, on the pistons 5, 6, respectively.

The annular spaces surrounding the pistons 5, 6 within the end stroke spaces 26, 27, and defined between the confronting shoulders of the cylinder and pistons, constitute in the form of Fig. 1 energy storage spaces. Communicating between the interior of the scavenger air re-. ceiver 30 and said energy storage spaces are apertures 28, 29. These are disposed substantial distances from the inner ends of the spaces 26, 27, longitudinally of the cylinder 4. As a result, when the pistons 5, 6 are moved outwardly from one another to the positions shown in Fig. 1, the slots 28, 29 will be adapted to provide communication between the scavenger air receiver interior and the spaces 26, 27. When, however, the pistons 5, 6 are moved toward one another during the expansion stroke of the pistons 2, 3, the annular spaces defined between the confronting shoulders will be sealed against the exit of air therefrom. As a result, the air therein will be compressed, to store up energy sufiicient to elfect return movement of the pistons 5, 6 after the pistons have moved to their inner dead center positions.

By reason of the arrangementillustrated, it will be seen that the operation ofthe Fig. 1 form is as follows:

Assuming that fuel has been fed to space'l3 through noule 14 by operation of a suitable fuel pump, not shown, said fuel, with pistons 2, 3, in the inner dead center positions shown in Fig. 1, will ignite, and combustion will take place, due to injection of the fuel into the highly compressed and heated air in the space 13. Pistons 2, 3, will accordingly be shifted outwardly in their expansion or power generating stroke, and pistons 5, 6 will shift toward one another in their compression stroke, thereby to force out of space 23 the air previously sucked thereinto, said air being forced into a compressor tank.

With the outward movement of the pistons 2, 3, a suction will be set up within the'spaces 17, 18,- causing air to be sucked from atmosphere through the valves 19, 20.

The inward movement of pistons.5, 6 will, as previously noted, cause energy to be stored in spaces 26, 27. At the conclusion of said inward movement, with the force of the expansion stroke of the combustion pistons depleted, the return movement energy will cause pistons 5, 6 to be shifted outwardly from one another, thereby returning the combustion pistons to their inner dead center positions for their next expansion stroke.

In this way, scavenger and charging pumps, defined by the stepped pistons and stepped diameters in the combustion cylinder, are automatically operative to draw air from the atmosphere into the scavenger air receiver, with said air subsequently being fed into the combustion chamber 13. At the same time, means for storing up return movement energy is automatically operable in the compressor cylinder group.

In Fig. 2, the combustion cylinder structure is identical to that of Fig. 1.- However, in this form the return movement energy is stored in the mid-length stroke space of the compressor cylinder rather than-in the end stroke spaces. The mid-length stroke space has been designated 23a, and located equal distances, in opposite directions, from the mid-length point of said space 23a are slots 34, 35. Space 23a, at its opposite ends, opens into end stroke spaces 26a, 27a of increased diameter relative to that of through the valves 38b, 39b, and the conduits 43,

space 230:. Suction valves 36, 37, are mounted in the walls of spaces 26a, 27a, respectively, to suck air from atmosphere into the end stroke spaces.

In this arrangement, the end stroke spaces 26a, 27a are partitioned as at 138, 139 to divide said end stroke spaces into side by side compartments. The suction valves 36, 37 open into the outer compartments. Mounted in the partitions are check valves 38, 39, respectively, permitting flow only from the outer to the inner or air collecting compartments, these being designated at 40 and 41. The inner compartments or pressure spaces are in constant communication with branch conduits 42, which lead to a common conduit extending to a compressor tank, not shown.

In operation of the Fig. 2 form of the invention, on the expansion stroke of the combustion pistons, pistons 5, 6 will move inwardly toward one another, compressing air within the space 23a to store up return movement energy. The compression of the air within the space 23a begins as soon as the pistons have passed the slots 34, 35. During this movement of the pistons, valves 38, 39 will open and valves 36, 37 will close, forcing air from the outer compartments into the compartments 40, 41, and then into the branch conduits 42 to the compressor tank.

Subsequently, at the completion of the expansion stroke of the combusion pistons, the energy stored within space 23a will effect return of the several pistons to their initial positions, and during this movement of the compressor pistons air will be drawn from the atmosphere through valves 36, 37, to be forced out of the compressor cylinder on the next exhaust stroke of the compressor piston.

In Fig. 3, the internal combustion cylinder again is formed exactly as in the Fig. 1 form. However, in this arrangement a second modification of the compressor cylinder group is provided, which allows for a two stage compression. The compressor cylinder comprises the mid-length stroke space 23b and the end spaces 26b and 27b. In about the same transverse substantially median plane of the cylinder, intermediate the opposite ends of the space 26b, a suction valve 36b and a discharge valve 38b are provided. Similarly there are a suction valve 37b and a discharge valve 39b in the cylinder space 27b. Furthermore, a suction valve 24b and a discharge valve 25b control the inlet and outlet of the mid-length space 23b. Valves 38b and 39b control conduits 43 and 44 which connect spaces 26b and 27b, respectively, with an intermediate cooler 45. The cooler opens in a passage through which air from the cooler can enter the space 23b via valve 24b to be discharged through the valve 25b into a compressed air tank not shown.

The stepped diameters of the compressor cylinder in this form of the invention define, at opposite ends of space 231), cylinder shoulders 14% confronting the shoulders 150, 150b, of the pistons 5, 6.

As a result, assuming that the combustion pistons are moving through their expansion stroke, the compressor pistons 5, 6 will move from the Fig. 3 positions thereof through their compression stroke. During the initial part of that movement of the pistons 5, 6 toward one another they will compress air in the spaces 26b, 27b, and will force the air thus compressed in a first stage 44, into the intermediate cooler 45 As soon as the large diameter outer end portions of the pistons 5, 6 pass the valves 36b, 37b, 38b and 39b, the inner ends of the spaces 26b, 27b will be sealed against the exit of air therefrom. Said spaces will immediately become, during the remaining part of the piston movement, energy storage spaces. In the meantime, the reduced piston portions operating in space 23b will compress the air in that space and discharge the air so compressed in the second stage through the discharge valve 25b.

After the conclusion of the compression stroke the energy stored within spaces 26b, 27b will force the pistons 5, 6 outwardly, to return the combustion pistons to their inner dead center positions.

During the movement of pistons 5, 6 away from one another air compressed in the first stage will enter the space 23b from the cooler 45 through valve 241), and when the piston shoulders 150 and will have passed the set of valves in the co-ordinate end spaces,

fresh air will be admitted to these spaces through the valves 36b and 37b.

It will be apparent to those skilled in the art that many alterations and modifications of the structure illustrated and described are possible without departure .from the essence and spirit .of the invention which, for that reason, shall not be limited but by the scope of the appended claims.

I claim:

1. In a combined internal combustion engine-air com pressor; two side by side groups of cylinders each defining a mid-length stroke space and two end stroke spaces of increased diameter as compared to the assosiated mid-length stroke space, a pair of pistons oppositely reciprocal in said cylinders of each of said groups, the pistons of each pair having confronting inner endportions working within and of the same diameter as the respective mid-length stroke space, and further having outer end portions working within and of the same diameter as the respective end stroke spaces, and means connecting each piston of one of said pairs with a corresponding one of the pistons of the other pair for simultaneous reciprocation in opposite directions relative to one another, one of said cylinder groups and its associated pistons constituting parts of a two-stroke internal combustion engine, and the other of said cylinder groups and its associated pistons constituting parts of an air compressor, at least one of said cylinders of said other group being provided with at least one aperture normally enabling flow of air into and out of said one cylinder and positioned so as to be obturated by the associated piston during movement of the latter in a direction tending to reduce the size of the corresponding stroke space, whereby any air remaining in the latter will be compressed upon continued movement of said last-named piston in'this direction for storing the required return movement energy thereof.

2. In a combined internal combustion engine-air compressor; two side by side groups of cylinders each defining a mid-length stroke space and two end stroke spaces of increased diameter as .compared with the associated mid-length stroke space, a pair of pistons oppositely reciprocal in said cylinders of each of said groups, the pistons of each pair having confronting inner end portions working within and of the same diameter as the respec-- tive mid-length stroke space, and further having outer end portions working within and of the same diameter as the respective end stroke spaces, and means connecting each piston of one of said pairs with a corresponding one of the pistons of the other pair for simultaneous reciprocation in opposite directions relative to one another,

one of said cylinder groups and its associated pistons constituting parts of a two-stroke internal combustion engine, and the other of said cylinder groups and its associated pistons constituting parts of an air compressor, each of those of said cylinders of said other group defining said end stroke spaces thereof being provided with at least one aperture normally enabling flow of air into and out of said last-named end stroke spaces, said apertures being positioned so as to be obturated by said outer end portions of the associated pistons, respectively, during movement ofthe latter in a direction tending to reduce said last-named end stroke spaces in size, whereby any air remaining in the same will be compressed upon continued movement of said last-named pistons in this direction for storing the required return movement energy thereof.

3. in a combined engine-compressor according to claim 2; said apertures being located adjacent the outermost ends of said last-named end stroke spaces so as to be free when the associated pistons are in their outer dead center positions, that one of said other group of cylinders defining said rnid-length stroke space thereof comprising a compression chamber for a single stage compression.

4. in a combined internal combustion engine-air compressor; two side by side groups of cylinders each defining a mid-length stroke space and two end stroke spaces of increased diameter as compared to the associated midlength stroke space, a pair of pistons oppositely reciprocal in said cylinders of each of said groups, the pistons of each pair having confronting inner end portions working within and of the same diameter as the respective midlength stroke space, and further having outer end portions working within and of the same diameter as the respective end stroke spaces, and means connecting each piston of one of said pairs with a corresponding one of the pistons. of the other pair for simultaneous reciprocation in opposite directions relative to one another, one of said cylinder groups and its associated pistons constituting parts of a two-stroke internal combustion engine, and the other of said cylinder groups and its associated pistons constituting parts of an air compressor, that one of said cylinders of said other group defining said midlength stroke space thereof being provided with a plurality of apertures normally enabling flow of air into and out said last-named mid-length stroke space, said apertures being positioned so as to be obturated by said inner end portions of the associated pistons during movement of the latter in a direction tending to reduce the size of said last-named mid-length stroke space, whereby any air remaining in the latter will be compressed upon continued movement of said last-named pistons in this direction for storing the required return movement energy thereof.

5. In a combined engine-compressor according to claim 4; said apertures being located adjacent the opposite ends of said one cylinder so as to be free when the associated pistons are in their outer dead center positions, those of said cylinders of said other group defining said end strokes spaces thereof being provided, respectively, with last-named pistons from their outer dead center positions ilowing through said valves into said compartments.

6, in a combined internal combustion engine-air compressor; two side by side groups of cylinders each defining a mid-length stroke space and two end stroke spaces of increased diameter as compared to the associated midlength stroke space, a pair of pistons oppositely reciprocal in said cylinders of each of said groups, the pistons of each pair having confronting inner end portions working within and of the same diameter as the respective midlength stroke space, and further having outer end portions working within and of the same diameter as the respective end stroke spaces, means connecting each piston of one of said pairs with a corresponding one of the pistons of the other pair for simultaneous reciprocation in tpposite directions relative to one another, one of said cylinder groups and its associated pistons constituting parts of a two-stroke internal combustion engine, the other of said cylinder groups and its associated pistons constituting parts of an air compressor, each of those of said cylinders of said other group defining said end stroke spaces thereof being provided at a substantially median location with at least one air inlet aperture and at least one air outlet aperture, said apertures being positioned so as to be obturated by said outer end portions of the associated pistons, respectively, subsequent to an initial part of the movement of the same in a direction tending to reduce said last-named end stroke spaces in size, and fluid conduit means establishing communication between said outlet apertures and that one of said cylinders of said other group defining said mid-length stroke space thereof, said last-named end stroke spaces during said initial part of the piston movement comprising compression chambers for the first stage of a two stage compression, the innermost portions of said last-named end stroke spaces, upon movement of said last-named pistons past said apertures, constituting the means for storing the return movement energy for these pistons, and said lastnamed mid-length stroke space comprising'a compression chamber for the second stage of said two stage compression.

7. In a combined engine-compressor according to claim 6; acooler incorporated in said fluid conduit means intermediate the junctions of the latter with said outlet apertures and said last named mid-length stroke space, both said inlet and outlet apertures being equipped with check valve means for controlling the flow of air therethrough.

References (Iited in the file of this patent UNITED STATES PATENTS 2,027,877 Pescara Jan. 14, 1936 2,139,425 Steiner Dec. 6, 1938 2,163,767 Steiner June 27, 1939 2,344,058 Pateras-Pescara Mar. 14, 1944 2,510,127 Mercier June 6, 1950 2,667,300 -Huber Jan. 26, 1954 FOREIGN PATENTS 434,921 Great Britain Sept. 11, 1935 

